This application relates to a method and a pharmaceutical composition for the treatment of schizophrenia.
Schizophrenia is a chronic disabling disease which may occur in nearly 1% of the population worldwide. While there remains some dispute as to the proper diagnostic criteria for schizophrenia, it is generally accepted that schizophrenia manifests itself in two distinct sets of symptoms, referred to as positive and negative symptoms. See, e.g. Carpenter et al., Am. J. Psychiatry 145: 578-583 (1988); Morrison et al., J. Nervous and Mental Disease 178: 377-384 (1990).
The so-called positive symptoms of schizophrenia are typified by delusions, hallucinations and formal thought disorder. These symptoms have proven responsive to treatments with antidopaminergic neuroleptic drugs such as haloperidol, chlorpromazine, thioridazine and others. In contrast, the negative symptoms, which are typified by alogia, anhedonia, asociality, apathy, avolition, and amotivation have not been responsive to drug treatments. Because of this, and the fact that negative symptoms once developed tend to persevere, some authors have characterized this condition is "irreversible." Carpenter, supra at 579. Surprisingly, therefore, a drug therapy which is effective to treat the negative symptoms of schizophrenia has now been found.